Work is in progress to study the optic nerve by electron microscopy and ancilliary techniques, concentrating on experimentally produced papilledema, optic atrophy, and glaucoma. The effect of high intracranial pressure has been studied, and it has been found that high intracranial pressure causes elevated pressure in the central retinal vein and to a lesser extent in the vortex veins. Because of this, blood flow is slowed in both the retinal and choroidal circulations. Further work will concentrate on producing papilledema, chronic glaucoma, and optic atrophy (both ascending and descending) in monkeys.